EPC-derived VECs (EPCdECs) are categorized into two group according to their effects on the proliferation of vascular smooth muscle cells: type-I pro-proliferative VECs and type-II anti-proliferative VECs. Type-II EPCdECs were converted to type-I VECs by repetitive subcultures. Not only subculture-dependent cellular stresses but also donor differences greatly affect the phenotype determination of VECs. By comparing the gene expression profiles of type-II EPCdEC of the first donor (EPC1dEC) at early passage and those of type-II EPC1dEC at late passage and EPCdEC of the second donor at early passage, characteristic gene expression patterns that discriminate Type-I and type-II EPCdECs will be comprehended. Overall design: Totally three samples of type-I EPC-derived VECs (EPC1dEC[P12], EPC2dEC[P7]) and type-II EPC-derived VEC (EPC1dEC[P7]) were subjected to the analyses.